Go talk to the RV dealers in your area. They are paying for the delivery services and they can arrange to have their own people (you) pick their RV's up at the factory. Before I ever bought a motorhome I rented a class C from a local dealer. I got to talking with the guy and he offered to allow me to go pick up motorhomes for him. He paid all expenses and paid you a flat fee of $300 for a trip from the plant in Indiana back to California. He would get 4 or 5 units at a time. He would fly everybody back to Indiana and then they would drive the units back in about 2 days. It's a good gig for if you're retired and looking for something to do, but $300 for 2 or 3 days of travel is not a lot of money.
I also ran into a guy at the gas pumps once that was delivering a class C. He had his own business but didn't have any employees. So he charged a per mile rate and then paid all his own expenses out of that. He was retired and said the money wasn't a bad supplemental income but he wasn't getting rich on it. But he also said during the summer he would make several trips to Alaska sometimes driving the big bus conversions and he loved it.
Both of these experiences were back when the economy was good. I would think if you didn't have any experience with the commercial vehicle delivery market, you may have a hard time breaking in right now unless you became an employee of a company already doing this. These companies not only deliver RV's, but they deliver school buses, transit buses, fire trucks, and all other similar type vehicles.